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x86/cpu: Clear VMX feature flag if VMX is not fully enabled
Now that IA32_FEAT_CTL is always configured and locked for CPUs that are known to support VMX[*], clear the VMX capability flag if the MSR is unsupported or BIOS disabled VMX, i.e. locked IA32_FEAT_CTL and didn't set the appropriate VMX enable bit. [*] Because init_ia32_feat_ctl() is called from vendors ->c_init(), it's still possible for IA32_FEAT_CTL to be left unlocked when VMX is supported by the CPU. This is not fatal, and will be addressed in a future patch. Signed-off-by: Sean Christopherson <sean.j.christopherson@intel.com> Signed-off-by: Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/20191221044513.21680-9-sean.j.christopherson@intel.com
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parent
7d37953ba8
commit
ef4d3bf198
1 changed files with 20 additions and 3 deletions
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@ -5,15 +5,21 @@
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#include <asm/msr-index.h>
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#include <asm/processor.h>
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#undef pr_fmt
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#define pr_fmt(fmt) "x86/cpu: " fmt
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void init_ia32_feat_ctl(struct cpuinfo_x86 *c)
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{
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bool tboot = tboot_enabled();
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u64 msr;
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if (rdmsrl_safe(MSR_IA32_FEAT_CTL, &msr))
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if (rdmsrl_safe(MSR_IA32_FEAT_CTL, &msr)) {
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clear_cpu_cap(c, X86_FEATURE_VMX);
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return;
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}
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if (msr & FEAT_CTL_LOCKED)
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return;
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goto update_caps;
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/*
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* Ignore whatever value BIOS left in the MSR to avoid enabling random
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@ -29,9 +35,20 @@ void init_ia32_feat_ctl(struct cpuinfo_x86 *c)
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if (cpu_has(c, X86_FEATURE_VMX) && IS_ENABLED(CONFIG_KVM_INTEL)) {
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msr |= FEAT_CTL_VMX_ENABLED_OUTSIDE_SMX;
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if (tboot_enabled())
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if (tboot)
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msr |= FEAT_CTL_VMX_ENABLED_INSIDE_SMX;
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}
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wrmsrl(MSR_IA32_FEAT_CTL, msr);
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update_caps:
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if (!cpu_has(c, X86_FEATURE_VMX))
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return;
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if ( (tboot && !(msr & FEAT_CTL_VMX_ENABLED_INSIDE_SMX)) ||
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(!tboot && !(msr & FEAT_CTL_VMX_ENABLED_OUTSIDE_SMX))) {
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pr_err_once("VMX (%s TXT) disabled by BIOS\n",
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tboot ? "inside" : "outside");
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clear_cpu_cap(c, X86_FEATURE_VMX);
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}
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}
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